There are some excellent resources available, and here are some excerpts:
Researchers are accumulating evidence that bonding with dogs has biological effects, such as elevated levels of the hormone oxytocin. “Oxytocin improves trust, the ability to interpret facial expressions, the overcoming of paranoia and other pro-social effects—the opposite of PTSD symptoms,” says Meg Daley Olmert of Baltimore, who works for a program called Warrior Canine Connection.
The animals draw out even the most isolated personality, and having to praise the animals helps traumatized veterans overcome emotional numbness. Teaching the dogs service commands develops a patient’s ability to communicate, to be assertive but not aggressive, a distinction some struggle with. The dogs can also assuage the hypervigilance common in vets with PTSD. Some participants report they finally got some sleep knowing that a naturally alert soul was standing watch.
A lot of Veterans with PTSD tend to isolate. They don’t engage. They build a defensive wall around themselves so they can feel safe. But dogs have an ability to shatter that wall. They’re friendly and non-judgmental. They invite interaction.” — Sandra Carson of Paws for Purple hearts
Wyman said the training process benefits not only the dog, but the Veteran who is doing the training.
“It’s an anxiety-reliever — a form of therapy,” she explained. “The dog helps the Veteran relax, de-stress and focus on something other than his symptoms.
“Training the future service dog is an end in itself,” Wyman observed, “but it’s also just one small aspect of our PTSD treatment program here. It’s a positive experience that helps the Veteran ‘open up’ and hopefully become more receptive to other forms of PTSD therapy. The dog is an avenue for getting the Veteran engaged in his treatment program."